1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright 2013-2015, Michael Ellerman, IBM Corp.
  4 */
  5
  6#define _GNU_SOURCE	/* For CPU_ZERO etc. */
  7
  8#include <elf.h>
  9#include <errno.h>
 10#include <fcntl.h>
 11#include <link.h>
 12#include <sched.h>
 13#include <signal.h>
 14#include <stdio.h>
 15#include <stdlib.h>
 16#include <string.h>
 17#include <sys/ioctl.h>
 18#include <sys/stat.h>
 19#include <sys/types.h>
 20#include <sys/utsname.h>
 21#include <unistd.h>
 22#include <asm/unistd.h>
 23#include <linux/limits.h>
 24
 25#include "utils.h"
 26
 27static char auxv[4096];
 28
 29int read_auxv(char *buf, ssize_t buf_size)
 30{
 31	ssize_t num;
 32	int rc, fd;
 33
 34	fd = open("/proc/self/auxv", O_RDONLY);
 35	if (fd == -1) {
 36		perror("open");
 37		return -errno;
 38	}
 39
 40	num = read(fd, buf, buf_size);
 41	if (num < 0) {
 42		perror("read");
 43		rc = -EIO;
 44		goto out;
 45	}
 46
 47	if (num > buf_size) {
 48		printf("overflowed auxv buffer\n");
 49		rc = -EOVERFLOW;
 50		goto out;
 51	}
 52
 53	rc = 0;
 54out:
 55	close(fd);
 56	return rc;
 57}
 58
 59void *find_auxv_entry(int type, char *auxv)
 60{
 61	ElfW(auxv_t) *p;
 62
 63	p = (ElfW(auxv_t) *)auxv;
 64
 65	while (p->a_type != AT_NULL) {
 66		if (p->a_type == type)
 67			return p;
 68
 69		p++;
 70	}
 71
 72	return NULL;
 73}
 74
 75void *get_auxv_entry(int type)
 76{
 77	ElfW(auxv_t) *p;
 78
 79	if (read_auxv(auxv, sizeof(auxv)))
 80		return NULL;
 81
 82	p = find_auxv_entry(type, auxv);
 83	if (p)
 84		return (void *)p->a_un.a_val;
 85
 86	return NULL;
 87}
 88
 89int pick_online_cpu(void)
 90{
 91	cpu_set_t mask;
 92	int cpu;
 93
 94	CPU_ZERO(&mask);
 95
 96	if (sched_getaffinity(0, sizeof(mask), &mask)) {
 97		perror("sched_getaffinity");
 98		return -1;
 99	}
100
101	/* We prefer a primary thread, but skip 0 */
102	for (cpu = 8; cpu < CPU_SETSIZE; cpu += 8)
103		if (CPU_ISSET(cpu, &mask))
104			return cpu;
105
106	/* Search for anything, but in reverse */
107	for (cpu = CPU_SETSIZE - 1; cpu >= 0; cpu--)
108		if (CPU_ISSET(cpu, &mask))
109			return cpu;
110
111	printf("No cpus in affinity mask?!\n");
112	return -1;
113}
114
115bool is_ppc64le(void)
116{
117	struct utsname uts;
118	int rc;
119
120	errno = 0;
121	rc = uname(&uts);
122	if (rc) {
123		perror("uname");
124		return false;
125	}
126
127	return strcmp(uts.machine, "ppc64le") == 0;
128}
129
130int read_debugfs_file(char *debugfs_file, int *result)
131{
132	int rc = -1, fd;
133	char path[PATH_MAX];
134	char value[16];
135
136	strcpy(path, "/sys/kernel/debug/");
137	strncat(path, debugfs_file, PATH_MAX - strlen(path) - 1);
138
139	if ((fd = open(path, O_RDONLY)) < 0)
140		return rc;
141
142	if ((rc = read(fd, value, sizeof(value))) < 0)
143		return rc;
144
145	value[15] = 0;
146	*result = atoi(value);
147	close(fd);
148
149	return 0;
150}
151
152int write_debugfs_file(char *debugfs_file, int result)
153{
154	int rc = -1, fd;
155	char path[PATH_MAX];
156	char value[16];
157
158	strcpy(path, "/sys/kernel/debug/");
159	strncat(path, debugfs_file, PATH_MAX - strlen(path) - 1);
160
161	if ((fd = open(path, O_WRONLY)) < 0)
162		return rc;
163
164	snprintf(value, 16, "%d", result);
165
166	if ((rc = write(fd, value, strlen(value))) < 0)
167		return rc;
168
169	close(fd);
170
171	return 0;
172}
173
174static long perf_event_open(struct perf_event_attr *hw_event, pid_t pid,
175		int cpu, int group_fd, unsigned long flags)
176{
177	return syscall(__NR_perf_event_open, hw_event, pid, cpu,
178		      group_fd, flags);
179}
180
181static void perf_event_attr_init(struct perf_event_attr *event_attr,
182					unsigned int type,
183					unsigned long config)
184{
185	memset(event_attr, 0, sizeof(*event_attr));
186
187	event_attr->type = type;
188	event_attr->size = sizeof(struct perf_event_attr);
189	event_attr->config = config;
190	event_attr->read_format = PERF_FORMAT_GROUP;
191	event_attr->disabled = 1;
192	event_attr->exclude_kernel = 1;
193	event_attr->exclude_hv = 1;
194	event_attr->exclude_guest = 1;
195}
196
197int perf_event_open_counter(unsigned int type,
198			    unsigned long config, int group_fd)
199{
200	int fd;
201	struct perf_event_attr event_attr;
202
203	perf_event_attr_init(&event_attr, type, config);
204
205	fd = perf_event_open(&event_attr, 0, -1, group_fd, 0);
206
207	if (fd < 0)
208		perror("perf_event_open() failed");
209
210	return fd;
211}
212
213int perf_event_enable(int fd)
214{
215	if (ioctl(fd, PERF_EVENT_IOC_ENABLE, PERF_IOC_FLAG_GROUP) == -1) {
216		perror("error while enabling perf events");
217		return -1;
218	}
219
220	return 0;
221}
222
223int perf_event_disable(int fd)
224{
225	if (ioctl(fd, PERF_EVENT_IOC_DISABLE, PERF_IOC_FLAG_GROUP) == -1) {
226		perror("error disabling perf events");
227		return -1;
228	}
229
230	return 0;
231}
232
233int perf_event_reset(int fd)
234{
235	if (ioctl(fd, PERF_EVENT_IOC_RESET, PERF_IOC_FLAG_GROUP) == -1) {
236		perror("error resetting perf events");
237		return -1;
238	}
239
240	return 0;
241}
242
243static void sigill_handler(int signr, siginfo_t *info, void *unused)
244{
245	static int warned = 0;
246	ucontext_t *ctx = (ucontext_t *)unused;
247	unsigned long *pc = &UCONTEXT_NIA(ctx);
248
249	/* mtspr 3,RS to check for move to DSCR below */
250	if ((*((unsigned int *)*pc) & 0xfc1fffff) == 0x7c0303a6) {
251		if (!warned++)
252			printf("WARNING: Skipping over dscr setup. Consider running 'ppc64_cpu --dscr=1' manually.\n");
253		*pc += 4;
254	} else {
255		printf("SIGILL at %p\n", pc);
256		abort();
257	}
258}
259
260void set_dscr(unsigned long val)
261{
262	static int init = 0;
263	struct sigaction sa;
264
265	if (!init) {
266		memset(&sa, 0, sizeof(sa));
267		sa.sa_sigaction = sigill_handler;
268		sa.sa_flags = SA_SIGINFO;
269		if (sigaction(SIGILL, &sa, NULL))
270			perror("sigill_handler");
271		init = 1;
272	}
273
274	asm volatile("mtspr %1,%0" : : "r" (val), "i" (SPRN_DSCR));
275}